OpenNMS

OpenNMS is a enterprise grade network management application, developed under the open source model. The project was started in 1999 and has reached full maturity. It is designed to monitor thousands of network connected devices and its scalability is amazing.

OpenNMS is easy to install, it uses a PostgreSQL database and works perfectly on Centos and Ubuntu. I have not tested it on other distros. It automatically discovers your network devices and can easily be configured to have your most import devices being monitored in a dashboard. It has a Geographical map which can show the actual locations of your devices as well.

Another interesting feature of OpenNMS is that it can can be configured to send you email messages when critical devices are down or serviceable again. The system can also monitor services on a server. It can for instance tell you if your web service is down although your web server is still online.

The best part of all is that OpenNMS will display all your information in very usefull graphs which can again be copied to your reports. The default install comes with several default reports but it is easy to create custom reports. Reports can be scheduled and configured to be emailed to you or you can just run them on the spot.

To make the best use of OpenNMS one has to enable SNMP on the network and that may have certain risks. I recommend that you only use SNMP version 3.